The goal of this STTR project is to develop innovative human tumor microenvironment (TM) assays for use as screening tools in the identification of new anti-tumor therapeutics. Novel assay technologies are needed for the discovery of new drugs, and combinations of drugs currently in clinical use, that are effective in the prevention and treatment of cancer. This Phase II application proposes to generate two human TM assays: a 24-well Intraepithelial Neoplasia-TM (IN-TM) assay and a second higher throughput 96-well IN-TM assay. The IN-TM assay is a realistic, three-dimensional, tissue-engineered human tumor model incorporating fluorescently marked squamous cell carcinoma (SCC) cells that enables sensitive fluorescence-based measurement and quantification of early intraepithelial neoplastic growth. In Specific Aim 1, a prototype 24-well IN-TM assay will be validated for measurement using commercially available filter-based or spectroscopic fluorescent plate reader instruments. In Specific Aim 2, the IN-TM assay will be adapted to a higher throughput 96-well format for larger scale screening. The IN-TM assay responses will be validated using depth-resolved multiphoton laser scanning microscopy (MPLSM) and second harmonic generation (SHG) imaging. The human IN-TM assay is a platform for the discovery of drugs that target specific oncogenic pathways, and/or the cancer stem cell niche. The development of these human IN-TM assays will provide the pharmaceutical industry and academic researchers with a biologically relevant, human cell-based, screening tool to evaluate novel cytotoxic or cytostatic agents and/or gene therapy strategies. These new assays and measurement methodologies represent significant technological advances in the cancer therapeutic screening field, and are anticipated to ultimately result in the identification of clinically relevant lead agents. Studies proposed in the Phase II will enable Stratatech Corporation to rapidly transition this powerful screening technology into commercial settings that will support the pharmaceutical industry. PUBLIC HEALTH RELEVANCE: Over half of all human cancers originate in stratified squamous epithelia. More than 1,000,000 cases of non- melanoma cancer of stratified squamous epithelia are expected to be diagnosed in 2007. A distinctive characteristic of human squamous cell carcinoma (SCC) cells is their rapid rate of proliferation and invasion into the stroma of affected epithelial tissues. Tumor recurrence near the site of the primary tumor is a predominant cause of treatment failure and patient death. Tissue-engineered human tumor models that recapitulate the microenvironment of normal surrounding epithelia and stroma have the potential to dramatically improve current understanding of tumor cell/normal cell interactions and enable the discovery of new anti-cancer drugs.